Fork assembly for lumber stackers

ABSTRACT

The fork assembly for lumber stackers includes a plurality of mechanized arms. Each mechanized arm includes a biasing assembly that provides a movable carrying surface onto the arm upper surface Such movable carrying surface is for example in the form of an endless belt, that biases an object deposited onto the arm towards a distal end thereof. The fork assembly according to the present invention prevents smaller pieces of lumber to rise when the fork assembly is retracted above a lumber stacker elevator during deposition of the lumber from the fork assembly to the elevator&#39;s platform. The present invention further allows creating stack of lumbers having different configurations.

FIELD OF THE INVENTION

[0001] The present invention relates to lumber stackers. Morespecifically, the present invention is concerned with a fork assemblyfor a lumber stacker.

BACKGROUND OF THE INVENTION

[0002] Lumber stacker apparatuses allowing stacking rows of wood lumbersare well known in the art of wood processing. A conventional lumberstacker 10 is described in FIG. 1 of the appended drawings.

[0003] The lumber stacker 10 comprises a lumber transfer apparatus 12mounted on top of a mounting frame structure 14, an elevator 16 mountedto said mounting frame structure 14, adjacent said lumber transferapparatus 12, and a fork assembly 17, so mounted to said mounting framestructure 14 as to reciprocate between a retracted position and anextended position.

[0004] The lumber transfer apparatus 12 is in the form of a conveyorbelt that includes conventional drive means 18 and a controller (notshown) that allows moving distanced parallel belts 20 (only one showed)in both forward and backward direction (see arrows 22 and 24)

[0005] The lumber transfer apparatus 12 allows aligning, side-by-side ina parallel relationship, wood lumbers 26 incoming from the distal end 28of the lumber transfer apparatus 12. The wood lumbers are positionedparallel to a first axis 30 and then moved by the belts 20 towards theelevator 16 (see arrow 24) in a direction perpendicular to the axis 30.

[0006] The lumber transfer apparatus 12 includes liftskids 32 to helpseparate the lumbers 26 into rows 34 having predetermined width. Theliftskids 32 allow accumulating lumbers onto the lumber transferapparatus belt 20 during the addition of a row of lumbers onto theplatform 40 of the elevator 16. The lumbers 26 may be positioned in rowsaccording to different needs and criteria. For example, the longest andwidest pieces of lumber may be positioned at both longitudinal ends ofthe row as can be seen in FIG. 1.

[0007] The proximate end 38 of the lumber transfer apparatus 12 isprovided with an angled portion 36 to facilitate the transfer of woodlumbers from the lumber transfer apparatus 12 to the fork assembly 17 asit will be explained hereinbelow.

[0008] The elevator 16 includes a platform 40 vertically movable along asecond axis 42 perpendicular to the plan of the belts 20. The platform40 is dimensioned to accommodate a row of lumbers from the row formingapparatus 17.

[0009] The fork assembly 17 comprises a carriage 44, provided withdriven wheels 46 or another drive means such as rails, and a pluralityof spaced arms 48 (only one shown) extending from the carriage 44 in aparallel relationship. The arms 48 are so configured, sized and spacedas to generally provide a surface for supporting and carrying a row oflumbers 26 incoming from the lumber transfer apparatus 16. Aconventional drive system 49 drives the carriage 44. Since drive systemsfor fork assemblies are believed to be well known in the art, they willnot be described herein in more detail.

[0010] The fork assembly 17 is so movably mounted to the support framestructure 14 under the transfer apparatus 16 and so configured and sizedthat its arms overlap the belts 20 of the transfer apparatus 12 with thearm and the belts 20 generally disposed in a common plan. Of course, therelative width and interspaces of the both the arms 48 of the forkassembly 17 and the belts 20 of the lumber transfer apparatus 12 areboth so chosen as to allow the overlapping relationship.

[0011] The carriage 44 and the drive system 49 allow reciprocal movementof the fork assembly 17 between an extended position, wherein the armsare positioned above the platform 40 of the elevator 16, to a retractedposition, wherein the arms of the fork are completely removed from abovethe platform 40.

[0012] In operation, lumbers of wood 26, usually incoming from a woodmill (not shown), are first aligned in rows 34 on the lumber transferapparatus 12. Translation of the belts 20 causes an aligned row 34 oflumbers 26 to be transferred to the fork assembly 17, which is then inits extended position over the platform 40 of the elevator 16. The forkassembly 17 is then translated in the direction of arrow 22 from itsextended position to its retracted position under the lumber transferapparatus 12. During the translation of the fork assembly 17, thelumbers 26 are prevented from translating back to the lumber transferapparatus 12 by a retractable mechanical stop assembly 50 and thereforeare forced to fall onto the platform 40.

[0013] The mechanical stop assembly 50 is mounted to the mounting framestructure 14 near the distal end 38 of the lumber transfer apparatus 12so as to block the path of the first lumber of the row when the forkassembly returns in its retracted position. The mechanical stop 50 ismade retractable so as to allow the passage of the lumber when the forkassembly 17 is moving from the retracted position to the extendedposition.

[0014] The mounting frame structure 14 can be any structure or bodyallowing to adequately position the lumber transfer apparatus 12, theelevator 16, the fork assembly 17 and the retractable stop 50 relativelyto each other in an operative relation.

[0015] Even though, the conventional lumber stacker 10 has beendescribed with its elements assembled to a mounting frame structure 14,other structures are known to be used to correctly position the elementsso as to provide a lumber stacker.

[0016] Of course, conventional lumber stackers in general, and morespecifically the lumber transfer apparatus 12, the elevator 16 and/orthe fork assembly 17, may take many other forms according to the priorart.

[0017] Since conventional lumbers stackers are believed to be well knownin the art, they will not be described herein in more detail.

[0018] A drawback of such lumber stackers from the prior art, and morespecifically to conventional fork assemblies, is that relatively narrowpieces of lumber may rise among other pieces in a row and overlap thedeposited row during the retraction of the fork apparatus.

[0019] Another drawback is that fork assemblies from the prior art donot allow complex arrangement of lumbers stacking.

OBJECTS OF THE INVENTION

[0020] An object of the present invention is therefore to provide animproved fork assembly for lumber stackers.

SUMMARY OF THE INVENTION

[0021] More specifically, in accordance with the present invention,there is provided a mechanized arm for a lumber stacker comprising:

[0022] a body;

[0023] a longitudinal arm mounted to the body and ***having a proximateend and a distal end and generally extending from the body from theproximate end along a longitudinal axis;

[0024] a biasing assembly mounted on the longitudinal arm; the biasingassembly defining a carrying surface on the longitudinal arm; thecarrying surface being movable along the longitudinal axis; and

[0025] a biasing assembly actuator in operative relation with thebiasing assembly for moving the carrying surface;

[0026] whereby an object deposited onto the longitudinal arm is biasedtowards the distal end of the arm by actuating the biasing assemblyusing the biasing assembly actuator.

[0027] According to a second aspect of the present invention, there isprovided a fork assembly for a lumber stacker comprising:

[0028] a plurality of mechanized arms according to the presentinvention; each of the plurality of mechanized arms being mounted to thelumber stacker as to be movable along each of the mechanized armlongitudinal axis; the plurality of mechanized arms being so positionedin a parallel relationship as to generally yield the mechanized armscarrying surfaces in a first plane;

[0029] at least one drive system mounted to the lumber stacker andcoupled to the plurality of mechanized arms for causing translationmovements of the plurality of mechanized arms along its respectivelongitudinal axis; and

[0030] a controller connected to both the at least one drive system andeach of the biasing assembly actuator for operating the at least onedrive system and each of the biasing assembly actuator.

[0031] According to a final aspect of the presenting invention, there isprovided a lumber stacker comprising:

[0032] a mounting structure;

[0033] a lumber transfer apparatus mounted to the mounting framestructure for receiving wood lumbers, aligning wood lumbers parallel toa second axis, in a second plan, and for moving wood lumbers, in thesecond plan, in a second direction perpendicular to the second axis; thelumber transfer apparatus including a series of parallel spaced conveyorbelts;

[0034] an elevator mounted to the mounting structure positioned adjacentthe lumber transfer apparatus, and including a platform movable along anaxis perpendicular to both the second plan and the second direction;

[0035] a fork assembly according to the second according to the presentinvention mounted to the mounting structure; the fork assembly being soconfigured and sized and so positioned relative to the lumber transferapparatus and the elevator as to be movable between a first positionwherein the arms of the fork assembly generally overlap the belts of thelumber transfer apparatus, to a second position wherein the arms extendabove the elevator;

[0036] a first stop mounted to the mounting structure so as to allowpassage of lumbers from the lumber transfer apparatus to the forkassembly when the fork assembly is in its second position and to forcelumbers on the fork assembly from the fork assembly to the platform ofthe elevator when the fork assembly is moved from the second position tothe first position; and

[0037] a second stop so mounted to the mounting structure opposite saidfirst stop relatively to the elevator as to be positioned in a movingpath of the fork assembly.

[0038] Other objects, advantages and features of the present inventionwill become more apparent upon reading the following non restrictivedescription of preferred embodiments thereof, given by way of exampleonly with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the appended drawings:

[0040]FIG. 1. which is labeled “Prior Art” is a side elevational view ofa conventional lumber stacker;

[0041]FIG. 2 is a perspective view of a fork assembly according to apreferred embodiment of the present invention;

[0042]FIG. 3 is a side elevational view of a mechanized arm of FIG. 2;

[0043]FIG. 4 is a bottom view of the mechanized arm of FIG. 3,

[0044]FIG. 5 is a reverse perspective view of the mechanized arm of FIG.3;

[0045]FIG. 6 is a side elevational view of a lumber stacker according toan embodiment of the present invention;

[0046]FIGS. 7a-7 d are partial side elevational views of the lumberstacker of FIG. 6, illustrating different stack configuration obtainedusing the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0047] Turning now to FIG. 2 of the appended drawings, a fork assembly100 according to a preferred embodiment of the present invention isshown.

[0048] The fork assembly 100 comprises a carriage 102, a drive system104 for the carriage (see FIG. 6), a plurality of mechanized arms 106(nine shown) pivotally mounted to the carriage 102, an a controller (notshown).

[0049] The carriage 102 is in the form of a metal frame provided withfour wheels 108 that allow the carriage 102 to be freely moved along theaxis 110.

[0050] Turning now briefly to FIG. 6, the drive system 104 allowstranslating the carriage 102 along the axis 110. The drive system 104includes a motor 103 and a drive mechanism 105 that transforms arotating movement of the motor into an axial one according to knownmethods. The drive system 104 is commanded and controlled by thecontroller (not shown), which is in the form of programmable logiccontroller (PLC) or a computer. Numerous control mechanisms are placedon the machine as to know the positions, speeds and status of thedifferent parts of the stacker 200.

[0051] The mechanized arms 106 are pivotally mounted to the carriage 102via a shaft 112. More specifically, the shaft 112 is rotatably mountedto the carriage 102 via shaft receiving brackets 114, while eachmechanized arm 106 is mounted to the shaft 112 via a mounting assembly116.

[0052] It is to be noted that the pivotally mounting of the mechanizedarms 106 to the carriage 102 is advantageous since it allows the arms106 to rise, and therefore be protected against breakage, when a loadedplatform underneath reach beyond the operational level for loading.

[0053] The shaft receiving brackets 114 include an aperture to receivethe shaft 112 and are secured to integral mounting blocks 118 of thecarriage 102 via screws 120 or other securing means such as welding.

[0054] Turning now to FIGS. 3 to 5, a mechanized arm 106 of the forkassembly 100 will be described in more detail.

[0055] The mechanized arm 108 comprises a body 122, a longitudinal arm124, a biasing assembly 126, and a biasing assembly actuator 128.

[0056] The body 122 includes a first aperture 130 to receive the shaft112, and therefore allows to pivotally mounting the mechanized arm 106to the carriage 102. The body 122 is preferably made of CHT 360 steelthat provides stiffness to the body 122. Of course, other metal ormaterials may alternatively be used.

[0057] The longitudinal arm 124 extends from the body 122 from aproximate end 132 to a distal end 134 generally along a longitudinalaxis 136. The longitudinal arm 124 includes a longitudinalbelt-receiving portion 138 extending laterally from the body 122. Thedistal end of the belt-receiving portion 138 includes a groove (notshown) that helps aligning the belt 144.

[0058] The longitudinal arm 124 advantageously has a triangular profiledefining a downward slope from the proximate end 132 to the distal end134 to ease the unloading of lumbers as it will be explainedhereinbelow.

[0059] The biasing assembly 126 includes a drive pulley 140 mounted tothe body 122 on the lateral side 142 of the belt-receiving portion 138so as to be complementary aligned therewith as it will be explainedhereinbelow and an endless belt 144 rotatably mounted to thebelt-receiving portion 138 of the arm 124 and to the drive pulley 140.The biasing assembly 126 also includes an upper guide pulley 146 and twobottom guide pulleys 148.

[0060] Finally, the biasing assembly 126 includes a belt idler assembly150 to tighten the belt 144 about the belt-receiving portion 138 andprevent slipping. Many belt idler assemblies can be used withoutdeparting from the spirit and nature of the invention. The belt idlerassembly 150 may be of the manual-adjusting type or of theself-adjusting type. Since belt idler assemblies are believed to be wellknown in the art, they will not be described further in.

[0061] The belt-receiving portion 138 on the longitudinal arm 124defines a carrying surface that is movable along the longitudinal axis136.

[0062] It is to be noted that the body 122 includes a slope portion 152and that the drive and upper guide pulleys 140 and 146 are sodimensioned and positioned relatively to the longitudinal arm 124 andthe slope portion 152 as to provide an upward slope portion 154 of thebelt 144. This optional slope portion 154 allows helping loading lumbersonto the longitudinal arm 106.

[0063] The pulleys 140, 146 and 148 and the belt idler assembly 150 areprovided with resilient belt contacting surface such as urethane toincrease friction with the belt 144.

[0064] As it will now become apparent to a person skill in the art,rotation of the drive pulley 140 allows biasing the carrying surfacefrom the proximate end 132 to the distal end 134 of the longitudinal arm106 or vice-versa.

[0065] The longitudinal arm 126 is advantageously in a material that islightweight, such as aluminium. Of course, other materials such as steelcan also be used.

[0066] Returning to FIG. 2, the biasing assembly actuator 128 includes amotor 156 connected to the controller, a first drive assembly 158 forthe transmission of the energy of the motor 156 to the shaft 112, and asecond drive assembly 160, for transmission of the energy of the shaft112 to the drive pulley 140.

[0067] The first drive assembly 158 includes a drive sprocket wheel 162,a driven sprocket wheel 164 and a first drive chain 166 therebetween tocoupled the drive and driven sprocket wheel for rotation in unison Thedrive sprocket wheel 162 is fixedly mounted to the shaft of the motor156. The driven sprocket wheel 164 is fixedly mounted to the shaft 112so as to be generally aligned with the first sprocket wheel 162.

[0068] The second drive assembly 160 includes a drive sprocket wheel 168fixedly mounted to the shaft 112 and rotatably mounted to the body 122,and a driven sprocket wheel 170 rotatably mounted to the body 122 andconnected to the drive sprocket wheel 168 via a second drive chain 172for rotation in unison.

[0069] Rotational movement of the driven sprocket wheel 170 istransmitted to the drive pulley 140 via the dumb-bell shaft 174 mountedto body 122 so as to be coaxially mounted to both the driven sprocketwheel 170 and the drive pulley 140.

[0070] Of course the use of sprocket wheels, gears and pulleys areinterchangeable in the transmission and drive assemblies, and so is theuse of drive chains and belts Other transmission means or drive assemblymay also alternatively be used. The motor 156 may be electric,hydraulic, pneumatic or mechanical.

[0071] Since the configuration and operation of drive assemblies and oftransmissions are believed to be well known in the art, they will not bedescribed herein in more detail.

[0072] In operation, when the carrying surfaces of the mechanized arms106 have to move in either a forward or a backward direction, a commandsignal is sent from the controller to the motor 156 that is energized.The rotation of the drive shaft of the motor 156 causes the rotation ofthe shaft 112 via the first drive assembly 158. The rotation of theshafts 112 then causes the rotation of the drive pulleys 140 via thesecond drive assemblies 160 of all the mechanized arms 106, which inturn, cause rotation of the belts 144 and therefore translation of thecarrying surfaces.

[0073] As it will now become more apparent, any object (not shown)deposited onto the longitudinal arms 106 is biased towards the distalends 134 of the fork assembly 100 by actuating the biasing assemblies126 using the biasing assembly actuators 128.

[0074] The controller is advantageously configured so as to detect thespeed of the belts 144 and therefore, indirectly the speed of thecarrying surface.

[0075] Alternatively, a chain may replace the belt. Also the completebelt system of the biasing assembly may be replaced, for example, by aseries of adjacent toothed wheels (not shown) that can be driven by anactuating system such as the one described hereinabove.

[0076] Of course, the carriage 102 may have other configurationsallowing supporting and translating the arms 106.

[0077] It is to be noted that the mechanized arms 106 are so mounted tothe carriage 102 in a parallel relationship as to yield their carryingsurfaces in a common plane.

[0078] The drive system 104 allows for causing translation movements ofthe mechanized arms 106 along the axis 120.

[0079] Alternatively, each mechanized arm 106 may be independentlymotorized by a plurality of drive systems. For example, independent railsystems (not shown) may be used A single or a plurality of motors couldpower such rail systems. An evener system (not shown) may however berequired to ensure that all mechanized arms extend simultaneously.

[0080] In addition to the management and operation of the biasingassemblies 126 of the mechanized arms 106, the controller alsoadvantageously commands the operation of the drive system 104.

[0081] As it will be explained hereinbelow in more detail, by varyingthe relative speed of the carriage 102 and of the biasing assemblies126, it is possible to obtain different configurations of stacks.

[0082] A lumber stacker 200 according to a preferred embodiment of thepresent invention will now be described with reference to FIG. 6. Since,the lumber stacker 200 is very similar to the conventional lumberstacker 10 described hereinabove, with the major exception of theincorporation of a fork assembly 100 according to the present invention,only the major differences will be discussed. Those differences will beenlightened in the course of the description of the operation of thelumber stacker 200.

[0083] In operation, the lumbers 26′, 26 and 26″ arrive side by side onthe lumber transfer apparatus 12. The pieces of lumber 26 are thenpositioned perpendicular to their travelling direction. When the numberof lumbers 26′, 26 and 26″ is sufficient to form a row, the liftskids 32stop new incoming pieces of lumber. The platform 40 of the elevator 16then lowers sufficiently to allow room for a new row of lumbers 26 andto ensure that the mechanized arms 106 of the fork assembly 100 will notcontact the top of the stack 202 taking form on the platform 40. It isto be noted that the fork assembly 100 is then in its retractedposition.

[0084] The carriage 102 then moves forward in the direction of theelevator 16 and the pieces of lumber fall one by one of the carryingsurface formed by the mechanized arms 106 since the proximate end 38 ofthe lumber transfer apparatus 12 includes a slope portion 39. When thecarriage 102 is at the end of its course, the fork assembly 100 is inits extended position, as illustrated in FIG. 6. The elevator platform40 then raises until the last row of the stack 202 contact themechanized arms 106.

[0085] Turning now to FIGS. 7A to 7D, four different ways to deposit arow from the fork assembly 100 to the platform 40, and therefore toachieve different stack configurations, are shown.

[0086] In FIG. 7A, the mechanical stop assembly 50 is positioned at ashort lateral distance from the mounting frame structure 14. Thecontroller is programmed and set to begin withdrawal of the forkassembly 100 from above the elevator 16 by commanding the drive system104 of the fork assembly 100. The controller detects when the firstpiece of lumber 26′ contact the mechanical stop 50, and then commandsthe biasing assembly actuators 128 to move the belts 144 of the forkassembly100 in a direction opposite the direction of withdrawal of thefork assembly 100 (see arrow 204 on FIG. 7A), with a speed slightlyinferior to the speed of the carriage 102. Since the pieces of lumber26, 26′ and 26″ are biased towards the distal end 134 of the mechanizedarms 106, the pieces of lumber 26, 26′ and 26″ are prevented fromraising under the pressure caused by the movement of the carriage 102and the abutment of the row of lumbers onto the stop 50 when the forkassembly 100 is moved to its retracted position. The pieces of lumber26′, 26 and 26″ are then gradually deposited onto the stack 202. Thismode of operation of the fork assembly 100 allows creating a solid stacknear the first mechanical stop assembly 50.

[0087] In FIG. 7B, the formation of a solid stack near the side of theplatform 40 opposite the first mechanical stop 50 is illustrated.

[0088] According to this second mode of operation of the fore assembly100, the controller commands the biasing assembly actuators 128 so as tomove the belts 144 in the direction of second mechanical stop 206,opposite the first mechanical stop 50. The pieces of lumber 26′, 26 and26″ are then biased towards the second mechanical stop 206. Thecontroller detects the contact of the last pieces of lumber 26″ with thestops 206 commands the drive system 104 to move the fork assembly 100 toits retracted position and the biasing assembly actuators 128 to movethe belts 144 of the fork assembly 100 in a direction opposite thedirection of withdrawal of the fork assembly (see arrow 204 on FIG. 7A),with a speed slightly superior to the speed of the carriage 102.

[0089] Since the pieces of lumber 26′, 26 and 26″ are biased towards thedistal end 134 of the mechanized arms 106, this ensure that the piecesof lumber 26, 26′ and 26″ are again prevented from raising under thepressure caused by the movement of the carriage 102 and the abutment ofthe row of lumber onto the stop 206 when the fork assembly 100 is movedto its retracted position. The pieces of lumber 26′, 26 and 26″ are thengradually deposited onto the stack 202.

[0090] The third mode of operation allows creating a square stack asillustrated in FIG. 7C.

[0091] The third mode of operation is similar to the second mode withthe following differences: at one point when the fork assembly 100 movestowards its retracted position, the controller commands the biasingassembly actuators 128 to stop biasing the pieces of lumber 26″, 26 and26″, until the leftmost piece of lumber 26′ contacts the firstmechanical stops 50. Then, the controller commands the biasing assemblyactuators 128 so as to move the belts 144 of the fork assembly 100 in adirection opposite the direction of withdrawal of the fork assembly 100,with a speed slightly inferior to the speed of the carriage 102. Thepieces of lumber 26′ and 26 still remaining on the mechanized arms arethen deposited onto the stack 202. It is to be noted that in order tosolidify the stack 202, it has been found advantageous to vary the timewhere the controller commands the biasing assembly actuators 128 to stopbiasing the pieces of lumber 26′ and 26.

[0092] Turning finally to FIG. 7D, a fourth mode of operation of thefork assembly 100 will be described.

[0093] The fourth mode of operation is similar to the second mode ofoperation, with the following differences: when the controller detectsthe contact of the last pieces of lumber 26″ with the stops 206, itcommands the drive system 104 to move the fork assembly to its retractedposition and the biasing assembly actuators 128 to move the belts 144 ofthe fork assembly 100 in a direction opposite to the direction ofwithdrawal of the fork assembly 100 with a speed slightly inferior tothe speed of the carriage 102.

[0094] This fourth mode of operation allows creating interspaces 208between the lumber 26′, 26 and 26″ deposited onto the stack 202.

[0095] In operation, the controller detects the position of the lumbers26′, 26 and 26″ relative to the mechanical stops 50 or 206 by detectingthe position and speed of the carriage 102 or the speed of the belts144. Alternatively, sensors (not shown) may be appropriately positionedso as to detect the position of the pieces of lumbers 26, 26′ and 26″.

[0096] Of course, the fork assembly 100 may be operated in a mode thatemulates a conventional fork assembly 17 by applying no tension onto themotor 156 and therefore not actuating the biasing assemblies 126.

[0097] Although the present invention has been described in reference tothe stacking of lumber, it can also be used to stack other generallyrectangular objects such as veneer, boxes and board sheets to name afew.

[0098] The present invention may optionally be used with a lumberstacker equipped with a sticker placer (not shown) that allows insertingstickers 210 in the stack 202 perpendicularly to the rows of lumbers 26(see for example FIGS. 7A-7D). Since sticker placer apparatuses arebelieved to be well known in the art, they will not be described hereinin more detail.

[0099] Of course, a plurality of interconnected controllers mayalternatively be used in place of the single controller described, eachcontrolling a specific element of the lumber stacker 200. Of course, oneof this plurality of controllers is then configured to manage theoverall operation of the lumber stacker.

[0100] Although the present invention has been described hereinabove byway of preferred embodiments thereof, it can be modified withoutdeparting from the spirit and nature of the subject invention, asdefined in the appended claims.

What is claimed is:
 1. A mechanized arm for a lumber stacker comprising:a body; a longitudinal arm mounted to said body and having a proximateend and a distal end and generally extending from said body from saidproximate end along a longitudinal axis; a biasing assembly mounted onsaid longitudinal arm; said biasing assembly defining a carrying surfaceon said longitudinal arm; said carrying surface being movable along saidlongitudinal axis, and a biasing assembly actuator in operative relationwith said biasing assembly for moving said carrying surface; whereby anobject deposited onto said longitudinal arm is biased towards saiddistal end of said arm by actuating said biasing assembly using saidbiasing assembly actuator.
 2. A mechanized arm as recited in claim 1,wherein said longitudinal arm includes a belt-receiving portion and saidbiasing assembly includes a drive pulley so mounted to said body as tobe complementary aligned with said belt-receiving portion, and anendless belt rotatably mounted to said drive pulley and saidbelt-receiving portion.
 3. A mechanized arm as recited in claim 2,wherein said biasing assembly further includes at least one of an upperguide pulley mounted to said body near said proximate end of saidlongitudinal arm and a bottom guide pulley mounted to said longitudinalarm below said belt-receiving portion.
 4. A mechanized arm as recited inclaim 3, wherein said biasing assembly is so position relatively to saiddrive pulley as to define an upward slope portion of said belt.
 5. Amechanized arm as recited in claim 2, wherein said biasing assemblyfurther includes a belt idler assembly.
 6. A mechanized arm as recitedin claim 1, wherein said longitudinal arm has a generally triangularprofile defining a downward slope from said proximate end to said distalend of said longitudinal arm.
 7. A fork assembly for a lumber stackercomprising: a plurality of mechanized arms as recited in claim 1, eachof said mechanized arms being mounted to the lumber stacker as to bemovable along each of said mechanized arm longitudinal axis; saidplurality of mechanized arms being so positioned in a parallelrelationship as to generally yield said mechanized arms carryingsurfaces in a first plane; and at least one drive system mounted to thelumber stacker and coupled to said mechanized arms for causingtranslation movements of said plurality of mechanized arms along itsrespective longitudinal axis.
 8. A fork assembly as recited in claim 7,further comprising a controller connected to both said at least onedrive system and each of said biasing assembly actuator for operatingsaid at least one drive system and each of said biasing assemblyactuator.
 9. A fork assembly as recited in claim 8, wherein saidcontroller further allows determining a relative speed between each ofsaid carrying surface of said plurality of mechanized arms and saidplurality of mechanized arms.
 10. A fork assembly as recited in claim 7,further comprising a carriage so mounted to said at least one drivesystem as to be movable along said longitudinal axis; said plurality ofmechanized arms being mounted to said carriage; whereby, operation ofsaid at least one drive system causing translation of said plurality ofmechanized arms along said longitudinal axis.
 11. A fork assembly asrecited in claim 10, wherein said plurality of mechanized arms beingpivotally mounted to said carriage.
 12. A fork assembly as recited inclaim 10, wherein said longitudinal arm includes a belt-receivingportion and said biasing assembly includes a drive pulley so mounted tosaid body as to be complementary aligned with said belt-receivingportion and an endless belt rotatably mounted to said drive pulley andsaid belt-receiving portion.
 13. A fork assembly as recited in claim 12,wherein said biasing assembly actuator includes a motor and at least onedrive assembly for transmitting the energy of said motor to said biasingassembly.
 14. A fork assembly as recited in claim 13, wherein saidplurality of mechanized arms being mounted to said carriage via arotatable mounting shaft positioned generally perpendicular to saidlongitudinal axes; said at least one drive assembly including a firstdrive assembly for transmitting the energy of said motor to saidrotatable mounting shaft, and a second drive assembly for transmittingthe energy of said rotatable mounting shaft to said biasing assembly;whereby actuation of said motor causes the actuation biasing assemblyvia said first and second drive assembly.
 15. A fork assembly as recitedin claim 14, wherein said first drive assembly includes a first drivewheel mounted to a drive shaft of said motor, and a first driven wheelfixedly mounted to said rotatable mounting shaft and being coupled tosaid first drive wheel for rotation in unison; said second driveassembly includes a second drive wheel fixedly mounted to said mountingshaft and rotatably mounted to said body, a second driven wheelrotatably mounted to said body and coupled to said second drive wheelfor rotation in unison, and a shaft mounted to said body and coaxiallymounted to said second driven wheel and said drive pulley.
 16. A lumberstacker comprising: a mounting structure; a lumber transfer apparatusmounted to said mounting frame structure for receiving wood lumbers,aligning wood lumbers parallel to a second axis, in a second plan, andfor moving wood lumbers, in said second plan, in a second directionperpendicular to said second axis; said lumber transfer apparatusincluding a series of parallel spaced conveyor belts; an elevatormounted to said mounting structure positioned adjacent said lumbertransfer apparatus and including a platform movable along an axisperpendicular to both said second plan and said second direction; a forkassembly as recited in claim 2 mounted to said mounting structure, saidfork assembly being so configured and sized and so positioned relativeto said lumber transfer apparatus and said elevator as to be movablebetween a first position wherein said arms of said fork assemblygenerally overlap said belts of said lumber transfer apparatus, to asecond position wherein said arms extend above said elevator; a firststop mounted to said mounting structure so as to allow passage oflumbers from said lumber transfer apparatus to said fork assembly whensaid fork assembly is in its second position and to force lumbers onsaid fork assembly from said fork assembly to said platform of saidelevator when said fork assembly is moved from said second position tosaid first position; and a second stop so mounted to said mountingstructure opposite said first stop relatively to said elevator as to bepositioned in a moving path of said fork assembly